The present invention relates to a defect observation device.
In a manufacturing process for a semiconductor device, if a foreign matter or a pattern defect such as a short circuit or a disconnection (hereinafter the foreign substance and the pattern defect are called “defect”) exists on a wafer which is a semiconductor substrate, a failure such as an insulation failure or a short circuit of wiring occurs. Since those defects are mixed in the wafer due to various causes attributable to a manufacturing process, it is important to detect the defects generated during the manufacturing process at an early stage, to identify a generation source, and to prevent a decrease in yield for mass production of the semiconductor device.
A method widely operated for identifying the defect cause will be described. First, a defect inspection device identifies a defect position on the wafer, observes and classifies a corresponding defect based on coordinate information on the identified defect position in detail, and compares the observed and classified defect with database to estimate the defect cause.
An SEM (Scanning Electron Microscope) is mainly used for defect observation. However, since there is a deviation between a coordinate system of the SEM and coordinate systems of other inspection devices, the defect observation device is equipped with the SEM and an optical microscope for coordinate alignment.
The optical microscope mounted on the defect observation device again inspects a defect detected by another inspection device to correct the coordinate information, and observes the defect in detail based on the corrected coordinate information. This makes it possible to correct the deviation of the coordinate system, improve a success rate of defect observation, and maintain a high throughput.
Japanese Unexamined Patent Application Publication No. 2012-127848 discloses a technique of shortening a time required for searching an SEM optical condition suitable for the defect observation and improving the throughput. More specifically, an initial optical condition of the defect observation device is set with the use of the inspection results of other defect inspection devices.